Surgical stapling device with parallel jaw closure

ABSTRACT

A surgical stapling device includes a tool assembly having an anvil, a cartridge assembly movable in relation to the anvil between open and clamped positions, a drive member, and a biasing mechanism or member. The biasing mechanism or member is configured to urge the cartridge assembly in relation to the anvil assembly to its fully open position to provide access to tissue during a surgical procedure.

FIELD

This technology is generally related to stapling devices and, more particularly, to surgical stapling devices with parallel jaw closure.

BACKGROUND

Surgical stapling devices for simultaneously cutting and stapling tissue are known in the art and are commonly used during surgical procedures to reduce the time required to perform the surgical procedure and to facilitate endoscopic access to a surgical site. Performing a surgical procedure endoscopically reduces the amount of trauma inflicted on a patient during the surgical procedure to minimize patient discomfort and reduce patient recovery times.

Typically, endoscopic stapling devices include a tool assembly having a first jaw, and a second jaw that can pivot in relation to the first jaw between an open or spaced position and a closed or clamped position. One of the first or second jaws supports a cartridge assembly that includes a plurality of staples and the other of the first or second jaws supports an anvil assembly that includes an anvil having staple deforming pockets that receive and form legs of the staples when the staples are ejected from the cartridge assembly.

In surgical procedures that require a stapling device including a tool assembly having jaws of an extended length, e.g., bariatric procedures and procedures involving the bowel or lungs, the surgical site is confined by the anatomy of the patient. This confinement may make it difficult to move the jaws of the tool assembly to a fully open position to receive and treat tissue.

SUMMARY

In aspects, this disclosure generally relates to a surgical stapling device including an anvil, a cartridge assembly movable in relation to the anvil between open and clamped positions, a drive member, and a biasing mechanism or member. The biasing mechanism or member is configured to urge the cartridge assembly in relation to the anvil assembly to its fully open position to provide access to tissue during a surgical procedure.

One aspect of this disclosure is directed to a tool assembly including an anvil, a cartridge assembly, a biasing mechanism, and a drive member. The anvil includes a body having a proximal portion and a distal portion. The body defines a central knife slot and includes a staple forming surface. The proximal portion of the body includes spaced side walls that define an anvil cavity. At least one of the side walls supports a boss that extends into the anvil cavity. The cartridge assembly includes a channel member and a staple cartridge. The channel member includes side walls and a base wall that define a channel cavity that receives the staple cartridge. At least one of the side walls of the channel member defines a slot that extends through a portion of the respective side wall. The cartridge assembly is movable in relation to the anvil to move the tool assembly from the open position to the clamped position. The biasing mechanism includes at least one spiral spring and a roller including a toothed portion. The roller is rotatably supported between the side walls of the anvil. The at least one spiral spring includes a coil portion and a first end. The coil portion of the at least one spiral spring is supported on the boss on the at least one side wall of the anvil in a position between the anvil and the channel member. The at least one spiral spring extends through the slot in the at least one side wall of the channel member. The first end of the at least one spiral spring is connected to the roller. The drive member includes a beam portion and a working end. The drive member is movable in relation to the anvil and the cartridge assembly from a retracted position to an advanced position to actuate the tool assembly. The beam portion includes a toothed rack that is engaged with the toothed portion of the roller such that movement of the drive member from its retracted position towards its advanced position causes rotation of the roller to wind the at least one spiral spring about the roller and move the tool assembly from the open position to the clamped position.

Another aspect of the disclosure is directed to a surgical stapling device including a handle assembly, an elongate body, and a tool assembly. The handle assembly includes a stationary handle. The elongate body has a proximal portion coupled to the handle assembly and a distal portion. The tool assembly is supported on the distal portion of the elongate body and includes an anvil, a cartridge assembly, a biasing mechanism, and a drive member. The anvil includes a body having a proximal portion and a distal portion. The body defines a central knife slot and includes a staple forming surface. The proximal portion of the body includes spaced side walls that define an anvil cavity. At least one of the side walls supports a boss that extends into the anvil cavity. The cartridge assembly includes a channel member and a staple cartridge. The channel member includes side walls and a base wall that define a channel cavity that receives the staple cartridge. At least one of the side walls of the channel member defines a slot that extends through a portion of the respective side wall. The cartridge assembly is movable in relation to the anvil to move the tool assembly from the open position to the clamped position. The biasing mechanism includes at least one spiral spring and a roller including a toothed portion. The roller is rotatably supported between the side walls of the anvil. The at least one spiral spring includes a coil portion and a first end. The coil portion of the at least one spiral spring is supported on the boss on the at least one side wall of the anvil in a position between the anvil and the channel member. The at least one spiral spring extends through the slot in the at least one side wall of the channel member. The first end of the at least one spiral spring is connected to the roller. The drive member includes a beam portion and a working end. The drive member is movable in relation to the anvil and the cartridge assembly from a retracted position to an advanced position to actuate the tool assembly. The beam portion includes a toothed rack that is engaged with the toothed portion of the roller such that movement of the drive member from its retracted position towards its advanced position causes rotation of the roller to wind the at least one spiral spring about the roller and move the tool assembly from the open position to the clamped position.

In aspects of the disclosure, the at least one spiral spring includes two spiral springs.

In some aspects of the disclosure, the toothed portion of the roller is centrally located on the roller and one of the two spiral springs is positioned on each side of the toothed portion of the roller.

In certain aspects of the disclosure, each of the side walls of the channel member defines a circular concavity and the coil of each of the two spiral springs is received within a respective one of the circular concavities on the side wall of the channel member.

In aspects of the disclosure, the anvil defines a longitudinal axis and supports spaced pins, and each of the spaced pins defines a longitudinal axis that is perpendicular to the longitudinal axis of the anvil.

In some aspects of the disclosure, each of the side walls of the channel member defines a bore, and each of the spaced pins of the anvil is received within one of the bores to maintain the anvil and the cartridge assembly in parallel alignment with each other as the tool assembly is moved between the open position and the clamped position.

In certain aspects of the disclosure, the working end of the drive member includes a first beam, a second beam, and a vertical strut interconnecting the first and second beams.

In aspects of the disclosure, the first beam engages the anvil and the second beam engages the cartridge assembly to define a maximum tissue gap between the anvil and the cartridge assembly during firing of the tool assembly.

Another aspect of this disclosure is directed to a tool assembly including an anvil, a cartridge assembly, and a drive member. The anvil includes a body having a proximal portion and a distal portion. The body defines a central knife slot and includes a staple forming surface. The proximal portion of the body includes spaced side walls that define an anvil cavity. Each of the side walls supports a distal pivot member and a proximal pivot member. The distal pivot member is longitudinally spaced from the proximal pivot member. The distal and proximal pivot members extend from the respective side walls of the channel member into the anvil cavity. The cartridge assembly defines a longitudinal axis and includes a channel member and a staple cartridge. The channel member includes side walls and a base wall that define a channel cavity that receives the staple cartridge. Each of the side walls of the channel member has a proximal portion that defines first and second slots. The first and second slots define axes that are substantially perpendicular to the longitudinal axis of the cartridge assembly. The first slots are longitudinally spaced from the second slots. Each of the first slots receives a respective one of the distal pivot members and each of the second slots receives a respective one of the proximal pivot members. The cartridge assembly is movable in relation to the anvil to move the tool assembly from its open position to its clamped position. The drive member includes a beam portion and a working end. The drive member is movable in relation to the anvil and the cartridge assembly from a retracted position to an intermediate position and subsequently to a clamped position to move the cartridge assembly in relation to the anvil from the open position to the clamped position. The first and second slots are configured such that that movement of the drive member from the retracted position to the intermediate position pivots the cartridge assembly in relation to the anvil into parallel alignment with the anvil and movement of the drive member from its intermediate position to its clamped position moves the cartridge assembly in relation to the anvil to the clamped position while maintaining the cartridge assembly in parallel relation to the anvil.

In aspects of the disclosure, the first slots include an angled portion that allows the cartridge assembly to pivot in relation to the anvil as the drive member moves from its retracted position towards the intermediate position.

In some aspects of the disclosure, biasing members are supported between the proximal portion of the anvil and the proximal portion of the channel member, the biasing members urging the cartridge assembly in relation to the anvil towards its clamped position.

In certain aspects of the disclosure, the channel member supports a ramp and the working end of the drive member includes a first beam, a second beam, and a vertical strut interconnecting the first and second beams.

In aspects of the disclosure, the first beam engages the anvil and the second beam engages the ramp of the cartridge assembly as the drive member is moved from its retracted position to its clamped position to move the cartridge assembly in relation to the anvil from its open position to its clamped position.

In some aspects of the disclosure, the biasing members include coil springs that are supported between the ramp of the cartridge assembly and the anvil.

Other features of the disclosure will be appreciated from the following description.

BRIEF DESCRIPTION OF DRAWINGS

Various aspects of the disclosure are described herein below with reference to the drawings, wherein:

FIG. 1 is a perspective view of exemplary aspects of a surgical stapling device according to aspects of the disclosure;

FIG. 2 is an enlarged view of the indicated area of detail shown in FIG. 1;

FIG. 3 is a side perspective exploded view of the tool assembly shown in FIG. 2;

FIG. 4 is an enlarged view of the indicated area of detail shown in FIG. 3;

FIG. 5 is a side perspective view of the anvil of the tool assembly shown in FIG. 3;

FIG. 6 is a side perspective view of a drive assembly of the tool assembly shown in FIG. 3;

FIG. 7 is a side perspective, cutaway view of a proximal portion of the tool assembly of the surgical stapling device shown in FIG. 1 with a channel of the tool assembly shown in phantom;

FIG. 8 is a cross-sectional view taken along section line 8-8 of FIG. 2;

FIG. 9 is a cross-sectional view taken along section line 8-8 of FIG. 2;

FIG. 10 is an enlarged view of the indicated area of detail shown in FIG. 9;

FIG. 11 is a cross-sectional view taken through the tool assembly of the stapling device of FIG. 1 as the tool assembly is moved to a clamped position;

FIG. 12 is an enlarged view of the indicated area of detail shown in FIG. 11;

FIG. 13 is a side perspective view of the tool assembly shown in FIG. 11 in an open position;

FIG. 14 is an enlarged view of the indicated area of detail shown in FIG. 13;

FIG. 15 is an alternative version of the tool assembly of the surgical stapling device shown in FIG. 1;

FIG. 16 is a side perspective exploded view of the tool assembly shown in FIG. 15;

FIG. 17 is a perspective view from above of the channel of the tool assembly shown in FIG. 16;

FIG. 18 is a side view of a proximal portion of the channel shown in FIG. 17;

FIG. 19 is a perspective view from below of a proximal portion of the anvil of the tool assembly shown in FIG. 16;

FIG. 20 is a perspective view from a distal end of the tool assembly shown in FIG. 15 with a staple cartridge removed from a cartridge assembly of the tool assembly and the tool assembly in the open position;

FIG. 21 is a side perspective view of the tool assembly shown in FIG. 15 in the open position with the anvil shown in phantom;

FIG. 22 is an enlarged view of the indicated area of detail shown in FIG. 21;

FIG. 23 is a side perspective view of the tool assembly shown in FIG. 15 in the an intermediate position between the open and clamped positions with the anvil shown in phantom;

FIG. 24 is an enlarged view of the indicated area of detail shown in FIG. 23;

FIG. 25 is a side perspective view of the tool assembly shown in FIG. 15 in the clamped position with the anvil shown in phantom; and

FIG. 26 is an enlarged view of the indicated area of detail shown in FIG. 25.

DETAILED DESCRIPTION

The disclosed surgical stapling device will now be described in detail with reference to the drawings in which like reference numerals designate identical or corresponding elements in each of the several views. However, it is to be understood that aspects of the disclosure described herein are merely exemplary of the disclosure and may be embodied in various forms. Well-known functions or constructions are not described in detail to avoid obscuring the disclosure in unnecessary detail. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the disclosure in virtually any appropriately detailed structure. In addition, directional terms such as front, rear, upper, lower, top, bottom, distal, proximal, and similar terms are used to assist in understanding the description and are not intended to limit the disclosure.

In this description, the term “proximal” is used generally to refer to that portion of the device that is closer to a clinician, while the term “distal” is used generally to refer to that portion of the device that is farther from the clinician. In addition, the term “endoscopic” is used generally used to refer to endoscopic, laparoscopic, arthroscopic, and/or any other procedure conducted through a small diameter incision or cannula. Further, the term “clinician” is used generally to refer to medical personnel including doctors, nurses, and support personnel. As used herein, the term “substantially parallel” includes true parallel as well as 10 degrees in either direction.

FIG. 1 illustrates exemplary aspects of the disclosed surgical stapling device shown generally as stapling device 10. Stapling device 10 includes a powered handle assembly 12, an elongate body 14, and a tool assembly 16. The elongate body 14 defines a longitudinal axis “X” and includes a proximal portion 14 a supported on the handle assembly 12 and a distal portion 14 b that supports the tool assembly 16. In some aspects of the disclosure, the tool assembly 16 forms part of a reload assembly 18 that includes a proximal body portion 18 a that is releasably coupled to the distal portion 14 b of the elongate body 14 of the stapling device 10. The proximal body portion 18 a includes a distal portion that supports the tool assembly 16. Although not shown, the tool assembly 16 can be coupled to the proximal body portion 18 a by a pivot member that facilitates articulation of the tool assembly 16 about an axis transverse to the longitudinal axis “X” of the elongate body 14. In alternate aspects of the disclosure, the tool assembly 16 is fixedly secured to the distal portion 14 b of the elongate body 14. For a description of exemplary aspects of the tool assembly, see, e.g., U.S. Pat. No. 6,241,139 (“the '139 patent”).

The handle assembly 12 of the stapling device 10 includes a stationary handle 20 and actuation buttons 22 that can be depressed to actuate the tool assembly 16, e.g., approximate the tool assembly 16, articulate the tool assembly 16, fire staples, etc. In aspects of the disclosure, batteries (not shown) are supported in the stationary handle 20 to power the handle assembly 12. It is envisioned that the stapling device 10 need not be powered but can also include a manually powered handle assembly such as described in the '139 patent.

FIGS. 2-4 illustrate the tool assembly 16 of the stapling device 10 in an open position. The tool assembly 16 includes an anvil 26, a cartridge assembly 28, and a drive member 30. The anvil 26 is fixedly secured to a distal end of the proximal body portion 18 a of the reload assembly 18 (or to the distal end of the elongate body 14). The cartridge assembly 28 is supported on the anvil 26 for movement between an open position (FIG. 1) and a clamped position (FIG. 11) and includes a staple cartridge 32 and a channel member 34. The channel member 34 includes side walls 36 and a base wall 38 that define a channel cavity 40 that receives the staple cartridge 32. The base wall 38 defines a knife slot 42 that extends through the channel member 34 along most of its length and includes a closed proximal and distal end. The knife slot 42 receives a portion of the drive member 30 to facilitate movement of the drive member 30 in relation to the anvil 26 and cartridge assembly 28 between retracted and advanced positions.

The channel member 34 has a proximal portion including a base 44 that is defined by a proximal portion 36 a (FIG. 3) of the side walls 36 of the channel member 34. I aspects of the disclosure, the width of the proximal portion 36 a of the side walls 36 in the base 44 of the channel member 34 is thicker than the width of the side walls 36 in a distal portion of the channel member 34. Each of the proximal portions 36 a of the side walls 36 in the base 44 includes an upper surface (as viewed in FIG. 3) that defines a bore 46 and a circular concavity 48. The bores 46 extend along an axis that is substantially perpendicular to a longitudinal axis of the cartridge assembly 28. The proximal portions 36 a of the side walls 36 are spaced from each other to define a channel 50 that communicates with the channel cavity 40 and receives the drive member 30 when the drive member 30 is in its retracted position. Each of the proximal portions 36 a of the side walls 36 of the channel member 34 also defines a circular slot 52 that extends through the side wall 36 a from an upper surface of the side wall 36 of the channel member 34 to the proximal end of the side wall 36 of the channel member 34 (FIG. 8).

The staple cartridge 32 is received within the channel cavity 40 and includes a cartridge body 54 that defines a central knife slot 56 and rows of staple pockets 58 on each side of the central knife slot 56. It is envisioned that two or more rows of staple pockets can be provided on each side of the central knife slot 56. It is also envisioned that the staple pockets 58 need not be aligned in rows but rather a variety of different arrays of staple pockets 58 can be defined on each side of the central knife slot 56. Each of the staple pockets 58 receives a staple and a pusher (not shown). For a more detailed description of the staple cartridge 32 including staples and pushers, see the '139 patent.

FIGS. 3 and 5 illustrate the anvil 26 of the stapling device 10 (FIG. 1) which includes a proximal portion 60 and a distal portion 62. The distal portion 62 of the anvil 26 defines a central knife slot 64 and includes a staple forming surface 66. The central knife slot 64 extends from the staple forming surface 66 and communicates with an internal channel (not shown) defined within the anvil 26. The central knife slot 64 and the internal channel (not shown) within the anvil 26 receive a portion of the drive member 30 as the drive member 30 is moved between its retracted and advanced positions.

The proximal portion 60 of the anvil 26 includes a pair of spaced side walls 70 that defines an anvil cavity 72 that receives the base 44 of the channel member 34 when the tool assembly is in its clamped position. The anvil cavity 72 is defined in part by a base wall 74 of the anvil 26 which supports two spaced pins 76 that extend upwardly from the base wall 74 (as viewed in FIG. 5) within the anvil cavity 72 towards the cartridge assembly 28. The pins 76 define an axis that is substantially perpendicular to a longitudinal axis of the anvil 26 and are received within the bores 46 formed in the proximal portions 36 a of the side walls 36 of the channel member 34. The side walls 70 also support bosses 78 that extend from the side walls 70 into the anvil cavity 72.

FIGS. 3 and 7 illustrate the proximal portion of the tool assembly 16 which includes a biasing mechanism 68. The biasing mechanism 68 includes a roller 80 and a pair of biasing members 82. The roller 80 is rotatably supported between the spaced side walls 70 of the anvil 26 and extends across the anvil cavity 72. The roller 80 has a toothed central portion 80 a. In aspects of the disclosure, each of the biasing members 82 includes a spiral spring 82 that has a coil portion 83 and a first end portion 84 that extends from the coil portion 83 and is secured to the roller 80. Each of the spiral springs 82 extends through the circular slot 52 in the channel member 34. The coil portion 83 of each of the spiral springs 82 is supported on one of the bosses 78 of the anvil 26 and sits within one of the circular concavities 48 (FIG. 3) defined in the proximal portions 36 a of the side walls 36 of the channel member 34. The outer surfaces of the spiral springs 82 engage inner surfaces of the channel member 34 to urge the cartridge assembly 28 away from the anvil 26 to move the tool assembly 16 to the open position. It is envisioned that the biasing mechanism 68 can have only a single spiral spring 82.

FIGS. 3 and 6 illustrate the drive member 30 which includes an elongate beam 31 having a proximal portion 86 and a distal portion 88. The proximal portion 86 is configured to receive a coupling member (not shown) that couples the drive member 30 to a control rod (not shown) included in the elongate body 14 of the stapling device 10 (FIG. 1). The control rod (not shown) is movable between a retracted position and an advanced position to move the drive member 30 between its retracted and advanced positions. The '139 Patent describes exemplary aspects of a coupling member and a control rod.

The distal portion 88 of the drive member 30 supports a working end 90 that is movable through the anvil 26 and the cartridge assembly 28 to actuate the tool assembly 16. In aspects of the disclosure, the working end 90 of the drive member 30 includes a first beam 92, a second beam 94, and a vertical strut 96 that couples the first beam 92 to the second beam 94. The vertical strut 96 supports a distally facing knife blade 98 and extends through the knife slot 64 of the anvil 26 and the knife slots 42 and 56 of the channel member 34 and the staple cartridge 32. The first beam 92 is received within the internal channel (not shown) of the anvil 26 and the second beam 94 is engaged with the channel member 34 of the cartridge assembly 28 such that movement of the drive member 30 from its retracted position towards its advanced position defines a maximum tissue gap between the staple cartridge 32 and the staple forming surface 66 (FIG. 5) of the anvil 26 as the tool assembly 16 is fired. It is noted that in this aspect of the disclosure, the working end 90 of the drive member 30 does not affect movement of the tool assembly 16 from its open position to its clamped position.

The elongate beam portion 31 of the drive member 30 includes a toothed rack 102. The toothed rack 102 is engaged with the toothed central portion 80 a of the roller 80. When the drive member 30 is moved from its retracted position to its advanced position, engagement between the toothed central portion 80 a of the roller 80 and the toothed rack 102 of the drive member 30 causes the roller 80 to rotate within the anvil cavity 72. Rotation of the roller 80 winds the spiral springs 82 about the roller 80 to move the coil portions 83 of the spiral springs 82 from an expanded condition (FIG. 8) to a contracted or condition (FIG. 12). When the spiral springs 82 are in their expanded condition, the coil portions 83 of the spiral springs 82 are positioned between the anvil 26 and the channel member 30 of the cartridge assembly 28 and urge the cartridge assembly 28 away from the anvil 26 to move the tool assembly 16 to the open position. When the spiral springs 82 are in their contracted condition, the coil portions 83 of the spiral springs 82 are contracted about the bosses 78 of the anvil 26 and the spiral springs 82 which extend through the slots 52 in the channel member 34 pulls the cartridge assembly 28 towards the anvil 26 such that the tool assembly 16 moves from its open position to its clamped position.

FIGS. 8-10 illustrate the tool assembly 16 in the open position. In the open position of the tool assembly 16, the drive member 30 is in a retracted position with the toothed rack 102 on the beam portion 100 of the drive member 30 engaged with the toothed central portion 80 a of the roller 80. When the drive member 30 is in the retracted position, the spiral springs 82 are in their expanded position such that the coil portions 83 of the spiral springs 82 urge the cartridge assembly 28 away from the anvil 26 to move the tool assembly 16 to the open position. The pins 76 of the anvil 26 are received within the bores 46 of the channel member 34 to maintain the anvil 26 in parallel alignment with the staple cartridge 32 of the cartridge assembly 28.

FIGS. 11-14 illustrate the tool assembly 16 in the clamped position. When the drive member 30 is moved from its retracted position towards its advanced position in the direction indicated by arrows “A” in FIGS. 11 and 12, engagement between the toothed rack 102 of the beam portion 100 of the drive member 30 and the roller 80 causes the roller 80 to rotate in the direction indicated by arrow “B” in FIG. 12 within the anvil cavity 72 of the anvil 26. As described above, the first end 84 of the spiral spring 82 is secured to the roller 80. Thus, as the roller 80 rotates within the anvil cavity 72, the first end 84 of the spiral spring 82 is wound about the roller 82 to contract the coil portions 83 of the spiral springs 82 about the bosses 78. As the spiral springs 82 are wound about the roller 80, the spiral springs 82 which extend through the circular slots 52 of the channel member 34 pulls the cartridge assembly 28 toward the anvil 26 in the direction indicated by arrow “C” in FIG. 11 to move the tool assembly 16 to the clamped position. As described above, the pins 76 move through the bores 46 in the channel member 34 to maintain the anvil 26 and the cartridge assembly 28 in parallel alignment as the cartridge assembly 28 moves towards the anvil 26. In the clamped position of the tool assembly 16, the staple forming surface 66 of the anvil 26 is in juxtaposed alignment with the staple cartridge 28.

It is envisioned that the cartridge assembly 28 could be fixedly secured to the elongate body 14 (FIG. 1) and the anvil 26 could be movable in relation to the elongate body 14 toward the cartridge assembly 28.

It is noted that the beam portion 100 of the drive member 30 immediately proximal of the toothed rack 100 includes a flat surface 112 (FIG. 6). After the tool assembly 16 is in the clamped position, the drive member 30 continues to move towards its advanced position to actuate the tool assembly 16. The flat surface 112 allows the beam portion 100 to pass over the roller 80 without rotating the roller 80.

FIGS. 15-26 illustrate an alternate version of the tool assembly of the stapling device 10 (FIG. 1) shown generally as tool assembly 216. The tool assembly 216 is like tool assembly 16 (FIG. 3) and includes an anvil 226, a cartridge assembly 228, and a drive member 230 (FIG. 16). The anvil 226 is fixedly secured to a distal end of the proximal body portion 18 a (FIG. 1) of the reload assembly 18 (or to the distal end of the elongate body 14) (FIG. 1). The cartridge assembly 228 is supported on the anvil 226 for movement between an open position (FIG. 15) and a clamped position (FIG. 25) and includes a staple cartridge 232 and a channel member 234. The channel member 234 includes side walls 236 and a base wall 238 that define a channel cavity 240 (FIG. 16) that receives the staple cartridge 232. The base wall 238 of the channel member 234 defines a knife slot 242 (FIG. 17) that extends through the channel member 234 along most of its length and includes a closed distal end. The knife slot 242 receives a portion of the drive member 230 to facilitate movement of the drive member 230 in relation to the anvil 226 and cartridge assembly 228 between retracted and advanced positions as described below.

FIGS. 15-18 illustrate the channel member 234 which includes a proximal portion that is defined by the side walls 236 of the channel member 234. The proximal portion of each of the side walls 236 defines first and second slots 250 and 252 (FIG. 18). The slots 252 are substantially linear and vertically oriented as viewed in FIG. 18. The slots 252 are also vertically oriented and include a linear portion 252 a and an angled portion 252 b. The angled portion 252 b of each of the slots 252 defines an angle θ with the axis of the linear portion. The angle θ is selected to allow the channel member 234 to pivot in relation to the anvil 226 from a pivoted position (FIG. 21) to a position in parallel alignment with the anvil 26 (FIG. 23) and can be from about 1 degree to about 5 degrees. In some aspects of the disclosure, angle θ is about 3 degrees.

The channel member 234 includes a ramp 255 that is supported between the proximal portion of the side walls 236. The ramp 255 defines a knife slot 255 a that is aligned with the knife slot 242 (FIG. 17) of the channel member 234 and supports a pair of spring mounts 258 which are positioned on each side of the knife slot 256 a.

The staple cartridge 232 is received within the channel cavity 240 of the channel member 234 and includes a cartridge body 254 that defines a central knife slot 256 and rows of staple pockets 257 on each side of the central knife slot 256. It is envisioned that two or more rows of staple pockets 257 can be provided on each side of the central knife slot 256. It is also envisioned that the staple pockets 257 need not be aligned in rows but rather a variety of different arrays of staple pockets 257 can be defined on each side of the central knife slot 256. Each of the staple pockets 257 receives a staple and a pusher (not shown). For a more detailed description of an exemplary staple cartridge 232 including staples and pushers, see the '139 Patent.

FIGS. 16 and 19 illustrate the anvil 226 which includes a proximal portion 260 and a distal portion 262. The distal portion 262 of the anvil 226 defines a central knife slot 264 and includes a staple forming surface 266. The central knife slot 264 extends through the staple forming surface 266 and communicates with an internal channel (not shown) defined within the anvil 226. The central knife slot 264 and the internal channel (not shown) within the anvil 226 receive a portion of the drive member 230 as the drive member 30 is moved between its retracted and advanced positions as described in further detail below.

The proximal portion 260 of the anvil 226 includes a pair of spaced side walls 270 that defines an anvil cavity 272 that receives the proximal portion of the channel member 234. The anvil cavity 272 is defined in part by a base wall 274 of the anvil 226. The base wall 274 defines a continuation of the central knife slot 264 such that the central knife slot 264 extends through a proximal end of the base wall 274. The base wall 274 includes spring mounts 276 (FIG. 19). The side walls 270 support pivot members 278 and 280 that extend from the side walls 270 inwardly into the anvil cavity 272. The pivot members 280 are positioned distally of the pivot members 278 and are received within the first slots 250 of the channel member 234. The pivot members 280 are received within the second slots 252 of the channel member.

FIG. 16 illustrates the drive member 230 which includes an elongate beam portion 231 including a proximal portion 286 and a distal portion 288. The proximal portion 286 is configured to receive a coupling member (not shown) that couples the drive member 230 to a control rod (not shown) included in the elongate body 14 of the stapling device 10 (FIG. 1). The control rod (not shown) is movable between a retracted position and an advanced position to move the drive member 230 between its retracted and advanced positions. The '139 Patent describes exemplary aspects of a coupling member and a control rod. The distal portion 288 of the elongate beam 231 supports a working end 290 that is movable through the anvil 226 and the cartridge assembly 228 to actuate the tool assembly 216. In aspects of the disclosure, the working end 290 of the drive member 230 includes a first beam 292, a second beam 294, and a vertical strut 296 that couples the first beam 292 to the second beam 294. The vertical strut 296 supports a distally facing knife blade 298 and extends through the knife slot 264 (FIG. 19) of the anvil 226 and the knife slots 242 (FIG. 17) and 256 of the channel member 234 and the staple cartridge 232, respectively. The first beam 292 is received within the internal channel (not shown) of the anvil 226 and the second beam 294 is engaged with the channel member 234 of the cartridge assembly 228 such that movement of the drive member 230 from its retracted position towards its advanced position moves the cartridge assembly 228 towards the anvil 226 to move the tool assembly 216 to the clamped position (FIG. 25) and define a maximum tissue gap between the staple cartridge 232 and the staple forming surface 266 (FIG. 5) of the anvil 226 as the tool assembly 216 is fired.

FIGS. 16 and 20 illustrate the biasing members 300 of the tool assembly 16. In aspects of the disclosure, the biasing members 300 include coil springs, e.g., 4, that are positioned between the proximal portions of the anvil 226 and the channel member 228. The coil springs 300 have a first end secured to the spring mounts 258 on the channel member 234 and a second end secured to the spring mounts 276 on the base wall 274 of the anvil 226. The coil springs 300 urge the proximal portions of the anvil 226 and channel member 234 of the cartridge assembly 228 apart to move the tool assembly 216 to its clamped position.

FIGS. 21 and 22 illustrate the tool assembly 216 in the open position. In the open position, the drive member 230 is in its retracted position with the working end 290 of the drive member 230 positioned proximally of the ramp 255, and the pivot members 278 and 280 are positioned within upper ends of the slots 250 and 252 of the channel member 234. The coil springs 300 which are engaged with the proximal portions of the anvil 226 and cartridge assembly 228 urge the proximal portions of the anvil 226 and the cartridge assembly 228 apart to move the tool assembly 216 to the open position.

FIGS. 23 and 24 illustrate the tool assembly 216 as the tool assembly 216 is moved from the open position towards the clamped position. When the drive member 230 is moved from its retracted position towards its advanced position in the direction indicated by arrows “E” in FIG. 23, the second beam 294 of the working end 290 of the drive member 230 engages and moves along an underside of the ramp 255 and pivots the cartridge assembly 228 about the pivot member 278 in the direction of arrow “F” in FIG. 23 towards the anvil 226 to an intermediate position in which the cartridge assembly 228 is in parallel alignment with the anvil 226. As the cartridge assembly 228 pivots to the intermediate position, the pivot members 280 move within the angled portions 252 b of the second slots 252 towards the linear portions 252 a of the slots 252.

FIGS. 25 and 26 illustrate the tool assembly 216 as the tool assembly 216 is moved from the intermediate position towards the clamped position. When the drive member 230 is moved from the position shown in FIG. 23 towards its advanced position in the direction indicated by arrows “E” in FIG. 25, the second beam 294 of the working end 290 of the drive member 230 continues to engage and move along the underside of the ramp 255 to urge the cartridge assembly 228 in the direction of arrows “G” in FIG. 25 towards the anvil 226 and towards the clamped position in which the cartridge assembly 228 is in juxtaposed parallel alignment with the anvil 226. As the cartridge assembly 228 moves to the clamped position, the pivot members 280 move within the linear portions 252 a of the slots 252 and the pivot members 278 move within the linear slots 250 to maintain the anvil 226 and the cartridge assembly 228 in substantially parallel alignment.

Although not shown, continued movement of the drive member 230 in relation to the anvil 226 and the cartridge assembly 228 towards its advanced position fires staples from the staple cartridge 232 of the cartridge assembly 228 into the gap defined between the staple forming surface 266 of the anvil 226 and the staple cartridge 232 of the cartridge assembly 228 and into the staple forming surface 266 of the anvil assembly 226. For a more detailed description of the operation and firing of an exemplary tool assembly, see the '139 Patent.

Persons skilled in the art will understand that the devices and methods specifically described herein and illustrated in the accompanying drawings are non-limiting exemplary aspects of the disclosure. It is envisioned that the elements and features illustrated or described in connection with one exemplary embodiment may be combined with the elements and features of another without departing from the scope of the present disclosure. As well, one skilled in the art will appreciate further features and advantages of the disclosure based on the above-described aspects of the disclosure. Accordingly, the disclosure is not to be limited by what has been particularly shown and described, except as indicated by the appended claims. 

What is claimed is:
 1. A tool assembly comprising: an anvil including a body having a proximal portion and a distal portion, the body defining a central knife slot and including a staple forming surface, the proximal portion of the body including spaced side walls defining an anvil cavity, at least one of the side walls supporting a boss that extends into the anvil cavity; a cartridge assembly including a channel member and a staple cartridge, the channel member including side walls and a base wall that define a channel cavity that receives the staple cartridge, at least one of the side walls of the channel member defining a slot that extends through a portion of the respective side wall, the cartridge assembly movable in relation to the anvil to move the tool assembly from an open position to a clamped position; a biasing mechanism including at least one spiral spring and a roller including a toothed portion, the roller rotatably supported between the side walls of the anvil, the at least one spiral spring including a coil portion and a first end, the coil portion of the at least one spiral spring supported on the boss on the at least one side wall of the anvil in a position between the anvil and the channel member, the at least one spiral spring extending through the slot in the at least one side wall of the channel member, the first end of the at least one spiral spring connected to the roller; and a drive member including a beam portion and a working end, the drive member movable in relation to the anvil and the cartridge assembly from a retracted position to an advanced position to actuate the tool assembly, the beam portion including a toothed rack that is engaged with the toothed portion of the roller, wherein movement of the drive member from its retracted position towards its advanced position causes rotation of the roller to wind the at least one spiral spring about the roller and move the tool assembly from the open position to the clamped position.
 2. The tool assembly of claim 1, wherein the at least one spiral spring includes two spiral springs.
 3. The tool assembly of claim 2, wherein the toothed portion of the roller is centrally located on the roller and one of the two spiral springs is positioned on each side of the toothed portion of the roller.
 4. The tool assembly of claim 2, wherein each of the side walls of the channel member defines a circular concavity, and the coil of each of the two spiral springs is received within a respective one of the circular concavities on the side wall of the channel member.
 5. The tool assembly of claim 1, wherein the anvil defines a longitudinal axis and supports spaced pins, each of the spaced pins defining a longitudinal axis that is perpendicular to the longitudinal axis of the anvil.
 6. The tool assembly of claim 5, wherein each of the side walls of the channel member defines a bore, and each of the spaced pins of the anvil is received within one of the bores to maintain the anvil and the cartridge assembly in parallel alignment with each other as the tool assembly is moved between the open position and the clamped position.
 7. The tool assembly of claim 1, wherein the working end of the drive member includes a first beam, a second beam, and a vertical strut interconnecting the first and second beams, the first beam engaging the anvil and the second beam engaging the cartridge assembly to define a maximum tissue gap between the anvil and the cartridge assembly during firing of the tool assembly.
 8. A surgical stapling device comprising: a handle assembly including a stationary handle; an elongate body having a proximal portion and a distal portion, the proximal portion coupled to the handle assembly; and a tool assembly supported on the distal portion of the elongate body, the tool assembly including: an anvil including a body having a proximal portion and a distal portion, the body defining a central knife slot and including a staple forming surface, the proximal portion of the body including spaced side walls defining an anvil cavity, at least one of the side walls supporting a boss that extends into the anvil cavity; a cartridge assembly including a channel member and a staple cartridge, the channel member including side walls and a base wall that define a channel cavity that receives the staple cartridge, at least one of the side walls of the channel member defining a slot that extends through a portion of the respective side wall, the cartridge assembly movable in relation to the anvil to move the tool assembly from an open position to a clamped position; a biasing mechanism including at least one spiral spring and a roller including a toothed portion, the roller rotatably supported between the side walls of the anvil, the at least one spiral spring including a coil portion and a first end, the coil portion of the at least one spiral spring supported on the boss on the at least one side wall of the anvil in a position between the anvil and the channel member, the at least one spiral spring extending through the slot in the at least one side wall of the channel member, the first end of the at least one spiral spring connected to the roller; and a drive member including a beam portion and a working end, the drive member movable in relation to the anvil and the cartridge assembly from a retracted position to an advanced position to actuate the tool assembly, the beam portion including a toothed rack that is engaged with the toothed portion of the roller, wherein movement of the drive member from its retracted position towards its advanced position causes rotation of the roller to wind the at least one spiral spring about the roller and move the tool assembly from the open position to the clamped position.
 9. The surgical stapling device of claim 8, wherein the tool assembly forms part of a reload assembly, the reload assembly including a proximal body portion that is releasably coupled to the distal portion of the elongate body.
 10. The surgical stapling device of claim 8, wherein the at least one spiral spring includes two spiral springs.
 11. The surgical stapling device of claim 10, wherein the toothed portion of the roller is centrally located on the roller and one of the two spiral springs is positioned on each side of the toothed portion of the roller.
 12. The surgical stapling device of claim 10, wherein each of the side walls of the channel member defines a circular concavity, and the coil of each of the two spiral springs is received within a respective one of the circular concavities on the side wall of the channel member.
 13. The surgical stapling device of claim 8, wherein the anvil defines a longitudinal axis and supports spaced pins, each of the spaced pins defining a longitudinal axis that is perpendicular to the longitudinal axis of the anvil.
 14. The surgical stapling device of claim 13, wherein each of the side walls of the channel member defines a bore, and each of the spaced pins of the anvil is received within one of the bores to maintain the anvil and the cartridge assembly in parallel alignment with each other as the tool assembly is moved between the open position and the clamped position. 